Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
1992-1-3
pubmed:abstractText
Phosphate is a competitive inhibitor of transesterification of GpC by the ribonuclease barnase. Barnase is significantly stabilized in the presence of phosphate against urea denaturation. The data are consistent with the existence of a single phosphate binding site in barnase with a dissociation constant, Kd, of 1.3 mM. The 2D 1H NMR spectrum of wild-type barnase with bound phosphate is assigned. Changes in chemical shifts and NOEs for wild type with bound phosphate compared with free wild type indicate that phosphate binds in the active site and that only small conformational changes occur on binding. Site-directed mutagenesis of the active site residues His-102, Lys-27, and Arg-87 to Ala increases the magnitude of Kd for phosphate by more than 20-fold. The 2D 1H NMR spectra of the mutants His-102----Ala, Lys-27----Ala, and Arg-87----Ala are assigned. Comparison with the spectra of wild-type barnase reveals that His-102----Ala and Lys-27----Ala have essentially the same structure as weild type, while some structural changes occur in Arg-87----Ala. It appears that phosphate binding by barnase is effected mainly by positively charge residues including His-102, Lys-27, and Arg-87. This may have applications for the design of phosphate binding sites in other proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11348-56
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Characterization of phosphate binding in the active site of barnase by site-directed mutagenesis and NMR.
pubmed:affiliation
Cambridge IRC for Protein Engineering, University Chemical Laboratory, U.K.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't